1. Field of the Invention
The present invention relates to a thin-film magnetic head for recording signals on and reproducing signals from a magnetic recording medium, the thin-film magnetic head being of a laminated structure comprising magnetic layers, a coil conductor, a gapping layer, and insulating layers which are successively deposited and etched as thin films on a substrate, with the gapping layer having an end face positioned for sliding contact with the magnetic recording medium, and more particularly to an improved structure of the coil conductor in the thin-film magnetic head.
2. Description of the Prior Art
There have heretofore been developed various magnetic recording and reproducing apparatus for recording and reproducing various signals. As recent years have seen miniaturization and diversification in the shape of magnetic recording mediums, efforts have also been made to develop magnetic heads suitable for recording information on and reproducing recorded information from such magnetic recording mediums. For example, there is known a small-size disc-shaped magnetic recording medium in which the intermost circular recording track has a radius of 15 mm and the outermost circular recording track has a radius of 20 mm. The magnetic heads for recording signals on and reproducing signals from such small-size disc-shaped magnetic recording mediums are required to be smaller in size. To meet this requirement, thin-film magnetic heads are with increasing frequency being used in place of conventional bulk-type magnetic heads. The thin-film magnetic heads are finding wide use as smaller-size magnetic heads also for their multichannel recording and reproducing capability.
The thin-film magnetic head is manufactured in the manner described below. A lower magnetic layer is deposited as a thin film on a substrate, and then a first insulating layer is deposited as a thin film on the lower magnetic layer. Thereafter, a coil conductor is deposited as a thin film on the first insulating layer and then etched into a coil, followed by the deposition of a second insulating layer as a thin film on the laminated body. After the first and second insulating layers are etched into a tapered configuration, a gapping layer and an upper magnetic layer are deposited as thin films on the lamination. For an improved signal recording and reproducing efficiency, it is preferable to keep the upper and lower magnetic layers spaced from each other by a sufficient distance and also to minimize the distance (known as the "throat height" (T.H.)) from the head surface for sliding contact with the magnetic recording medium to the outermost peripheral portion of the coil conductor. If the distance between the upper and lower insulating layers should be increased to a substantial extent, a resist film on the upper insulating layer would be etched and retracted at the time of etching the upper and lower insulating layers into a tapered shape at a certain taper angle. This would lead to the drawback that the outermost peripheral portion of the coil conductor closest to the sliding contact surface of the magnetic head would be thinned out upon etching. In order to prevent the thinned coil conductor from being burned out by a recording current flowing therethrough, the second insulating layer would have to be left on the surface of the coil conductor close to the sliding contact surface of the magnetic head for protecting the coil conductor from being etched. With such a proposed arrangement, however, the throat height would be increased, and good signal recording and reproducing efficiency would not be achieved.